Wire-Shaped 3D-Hybrid Supercapacitors as Substitutes for Batteries

We report a wire-shaped three-dimensional (3D)-hybrid supercapacitor with high volumetric capacitance and high energy density due to an interconnected 3D-configuration of the electrode allowing for large number of electrochemical active sites, easy access of electrolyte ions, and facile charge transport for flexible wearable applications. The interconnected and compact electrode delivers a high volumetric capacitance (gravimetric capacitance) of 73 F cm^-3 (2446 F g^-1), excellent rate capability, and cycle stability. The 3D-nickel cobalt-layered double hydroxide onto 3D-nickel wire (NiCo LDH/3D-Ni)//the 3D-manganese oxide onto 3D-nickel wire (Mn₃O₄/3D-Ni) hybrid supercapacitor exhibits energy density of 153.3 Wh kg^-1 and power density of 8810 W kg^-1. The red light-emitting diode powered by the as-prepared hybrid supercapacitor can operate for 80 min after being charged for tens of seconds and exhibit excellent electrochemical stability under various deformation conditions. The results verify that such wire-shaped 3D-hybrid supercapacitors are promising alternatives for batteries with long charge-discharge times, for smart wearable and implantable devices.